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Posted: Sat Feb 21, 2004 12:10 pm
by jarvo
hi,
very good site by the way.

im a total newbie when it comes to diy so please bear with me.

im looking to lay a patio that is 3.6m x 3.6m (13msq), using 40x40cm slabs/flag stones.
what are the correct quantities of sharp sand, Hardcore and cement i need.

ive worked it out as (25kg bags):
Sand = 34
Cement = 5
Hardcore = 34

does this sound way out?

Posted: Sat Feb 21, 2004 12:42 pm
by 84-1093879891
You can use the calculators I provide on the main site to work out just how much is needed in terms of bedding materials.

"Hardcore" is not a term I like to use on this site, as it is so non-specific that it can mean more or less anything. If you want to install a sub-base, then use a sub-base material, such as DTp1 or Crusher Run.

Now, using the Sub-base calculator and allowing for 200mm of spread to all edges, if you use a 75mm sub-base layer, then you need 2.4 tonnes of sub-base material, which is considerably more than your 34 bags @ 25kg (850kg).

Then, using the Bedding mix Calculator and assuming 100mm of spread to all edges, you will need around 160kg of cement (7 bags @ 25kg), 570kg of grit sand (23 bags) and 850kg of gravel or additional grit sand (34 bags).

I don't know how you arrived at your figures, but you've underestimated by quite a bit, you've not allowed for wastage, and it would be much more cost-effective to buy the sub-base material and the sands/gravels in Bulk Bags, rather than the paltry 25kg bags.

You also need to consider what you will use as jointing.

Posted: Tue Feb 24, 2004 3:03 pm
by jarvo
thank you,

i got the estimated measurments from a local hardware stores online guide on how to lay a patio.

they were showing the requiments for a 2.7m x 3.6m patio, i just increased the quantities accordingly.

the problem is ive read a few guides and each one suggest different methods and different material requirments.

The sub base layer it reccomended was 50mm deep, which work out at 1.3ton on your calculator (first time i used your calculator it give me 0.3 ton) must have been a typo by me.

i was looking at the smaller bags as just a guide to the correct weight, the bulk bags didnt have a weight. (looking at a similar retailer its says equal to 40 bags).
i would buy the bulk bags as they worked out at least £10 cheaper.


thanks for the advice.

im going to get help from a builder i know, i just wanted to have an idea of what he was talking about.

:D